How do you set the brush up to paint leaves?

Hi, I've been following along with some of the demos on youtube and trying to paint the same things. I've got a bit stuck trying to paint leaves in the same way, though.
https://www.youtube.com/watch?v=PBO2hNv_tTE?t=1788 here's a timestamp to what I'm struggling to replicate.
How do you make that custom brush shape then reuse it over and over to draw leaves? I can't follow what settings you're changing

Here's what I've got so far on my first attempt using Verve! It's very fun to use and I think I've got the hang of the basics.
https://www.youtube.com/watch?v=PBO2hNv_tTE?t=1788 here's a timestamp to what I'm struggling to replicate.
How do you make that custom brush shape then reuse it over and over to draw leaves? I can't follow what settings you're changing


Here's what I've got so far on my first attempt using Verve! It's very fun to use and I think I've got the hang of the basics.